Effect of Tub in Regulating Body Weight of Rats
'Tub', a protein expressed in neurons of hypothalamic nuclei, is a non-functional mutation in the obese, hyperinsulinic 'tubby' mouse. This protein is normally found in a region of the brain that regulates energy balance; and may be an intermediary in the intracellular signaling cascade of the insulin hormone in these regions. The purpose of this project is to characterize the function of 'tub' in the hypothalamus and validate tub's role in the regulation of body weight in genetically normal, non-obese animals. The use of viral vector technology helped determine if overexpression results in enhanced responsiveness to endogenous or exogenous insulin. Experimental procedures included injecting experimental and control rats with amplicons containing vectors for 'tub' tagged with HA and green fluorescent protein (GFP) or solely GFP, respectively, into the hypothalamic region, where the GFP is used as a reporter gene. Food intake and body weight were measured throughout the experimental period. Tissue analysis included Western blotting, fluorescent microscopy, and immunohistochemistry. There was no significant difference in the body weight and food intake between rats injected with HA-TUB-GFP and GFP or implanted with Artificial Cerebral Spinal Fluid (ACSF) and insulin. However, further research will be conducted to confirm the dose response range of exogenous insulin in the hypothalamic region. Future work will reveal whether 'tub' can blunt diet-induced obesity, which is a major factor of Type II Diabetes.
